Mr Burkle, who recently bought a controlling stake in the Soho House chain of private members' clubs, made the investment through his Yucaipa fund.

The deal, the exact value of which is not known, sees the retail billionaire take a non-controlling stake in the business, whose clients include actor Daniel Craig, film maker Danny Boyle, and television presenters Sarah Beeny and Mel Giedroyc.

The investment will allow Independent – the product of a management buy-out from ICM in 2002 – to expand into a number of new areas including sport, representing golf and tennis players, as well as expand into Asia in due course.

Independent is also understood to be considering raising money for a film production fund, a process which will be eased as a result of Yucaipa's investment.

Prior to the investment, Independent was owned by its senior staff, led by co-chairman Duncan Heath, who, based on filings at Companies House, was the largest single shareholder.